Slotted electrode for an electron multiplier tube



J. MARCHET May 24, 1966 SLATTED ELECTRODE FOR AN ELECTRON MULTIPLIER TUBE 2 Sheets-Sheet 1 Filed Nov.

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p EL M Mm 1L T w m u LFmrh Y m: w

a mm m. m m m m F F JQJLJIJ K L B INVENTOR JACQUES MARCHET y 1966 J. MARCHET 3,253,182

SLATTED ELECTRODE FOR AN ELECTRON MULTIPLIER TUBE Filed Nov. 1, 1962 2 Sheets-Sheet 2 i E I I l ii i MD INVENTOR JACQUES MARCHET BY d-va z- AGEN United States Patent 3,253,182 SLOTTED ELECTRODE FOR AN ELECTRON MULTIPLIER TUBE Jacques Marchet, Brive, France, assignor to North American Philips Company, Inc., New York, N.Y., a corporation of Delaware 7 Filed Nov. 1, 1962, Ser. No. 234,727 Claims priority, application France, Nov. 3, 1961, 877,813 3 Claims. (Cl. 313-348) The invention relates to a slatted electrode for use in an electron multiplier, in which the edges lying nearest to each other and associated with successive elements of an electrode are arranged on either side of the support of said elements in planes at right angles to said support or in planes being at an acute angle to said support in the same quadrant as the elements. The invention furthermore relates to an electron-multiplier comprising two or more of such electrodes.

The relative positions of the elements of a slatted electrode described above is required for ensuring that the whole electron current is multiplied by each electrode and that part of the current does not skip an electrode. With a photo-electron multiplier it is furthermore important that the light produced by the electron flow on the anode or in the higher stages of the multiplier should not strike the electrode.

Hitherto the separate elements of the slatted electrode were soldered, which gave rise on the one hand to a ditficult and hence expensive, but not quite accurate construction, whereas on the other hand the many soldering areas produced a strong noise in the multiplier.

There is known a structure in which the elements of the electrodes are bent out of a metal tape after said elements have been punched loose on three sides. Then the sides of the electrodes are corrugated in order to ensure that the electrodes can capture all incident electrons. The deformation of the sides requires very accurate jigs, but owing to their resilience the dimensions cannot be fixed with great accuracy. Moreover, the assembly of a tube having a plurality of said electrodes can be performed only with difficulty.

The invention has for its object to provide a structure which is advantageous with respect to the known structures.

With a slatted electrode for use in an electron multiplier, in which the edges nearest to each other and associated with successive elements of an electrode are arranged on either side of the support of said elements in planes at right angles to said support or in planes being at an acute angle to said support in the same quadrant as the elements, the electrode consists, in accordance with the invention, of two fiat supporting frames lying side by side and forming each an integral structure with half of the slatted elements, which are formed by punching the supporting frame and by turning them around narrow tags by means of which they are connected with the long side of a supporting frame, while the elements of one supporting frame are located between those of the other supporting frame.

The two supporting frames according to the invention are preferably identical and have on each side half an element having a width of a/Z cos +e, wherein 2a is the central distance between the elements of one supporting frame, p the angle of inclination to the supporting frame and e the thickness of the supporting frame, while the central distance of the first whole element from the inner side of the transverse edge is equal to zr-i-e, the two supporting frames engaging each other so that at each of the ends of the electrode there is half an element.

3,253,182 Patented May 24, 1966 If an electron multiplier comprises two or more electrodes, the latter are shifted, in accordance with the invention, relatively to each'other-in the longitudinal direction, i.e. in the direction given by the elements of the preceding electrode, approximately over a distance of /2a, if 2a is the central distance between two elements of the same frame. In order to provide a simple assembly of such an electron multiplier, the electrodes are accommodated in supporting fillets having a rectangular rim, the length of which is equal to that of the electrodes plus /2a, the electrodes lying alternately at one end and at the other end.

The invention will be described more fully with reference to the drawing, in which FIG. 1 shows a single electrode according to the invention,

. FIGS. 2a and 2b show a single supporting frame in different phases of its manufacture,

FIG. 3 shows two successive electrodes in an electronmultiplier and FIG. 4 shows a tool for the formation of the supporting frames.

As shown in FIG. 1 the electrode is formed by an upper supporting frame A and a lower supporting frame B, each comprising five slatted elements al to a4 and b1 to b4 respectively and half an element a5 and respectively. It will be seen that the identical elements engage each other in opposite directions. The distance between the successive elements a and the angle of inclination (p are also indicated in the drawing and it is clearly apparent that the successive rims of two elements are located in planes substantially at right angles to the supporting frames.

FIG. 2a shows a single element M shaped in the form of a flat plate from which parts are punched so that four whole elements ml to m4 are formed, which have central distances of 2a, the width of each being a/cos (p. The width of half the element is a/cos pj+e. The fixed edge of the half element is at a distance of 2a+e from the centre line of the preceding whole element, wherein e is the thickness of the plate. The central distance of the first whole element from the inner side of the transverse edge BT of the supporting frame is a-i-e. The addition by the value e of this distance and the additional width of the half element are required to guarantee, also with the half elements, the correct positions of the free edges of the elements relative to each other. The elements ml to m4 are connected by narrow tags L with the long side BL of the supporting frame. These tags are deformed when the elements are turned through the angle (p. FIG. 2b shows the supporting frame in a sec tional view.

FIG. 3 shows two successive electrodes D1 and D2, which are shifted in the longitudinal direction over a distance b relatively to each other. To this end they are accommodated in rectangular supporting fillets F, having upright rims Pb and bent-over rims Fa, while the length d of the space inside the upright rims Fb is equal to l+d, if 1 is the length of the electrode. b is preferably equal to /2a.

As shown in FIG. 4 a metal strip T, in which the elements m l to m5 as shown in FIG. 2a are punched, is accommodated in the jig MD so that, when a stamper PD is urged downwards, the correct outer edge is cut off; at the same time the lower jig P and the upper jig Q, provided with teeth R and S respectively are urged towards each other so that the elements are bent over through the correct angle.

What is claimed is:

1. In an electron multiplier tube, a slatted electrode comprising two interengaging flat supporting frames each provided with a plurality of slat-like elements extending outwardly from both sides of said frame and forming an angle therewith not greater than 90, each of said elements being connected to one of said frames by a tag of smaller dimensions than the slat-like element which is integral therewith and the frame, alternate elements being connected to the respective frames and being spaced apart a given distance so that said elements interleave and are spaced from one another an equal distance.

2. A slatted electrode as claimed in claim 1, in which the two supporting frames are identical and have on one side a half element 'of a width of a/2 cos +e, wherein 2a is the central distance between the elements of a supporting frame, (,0 is the angle of inclination to the supporting frame, e is the thickness of the supporting frame, while the central distance of the last element from the inner side of the transverse edge is equal to a+e and the distance of the center line of the last whole element from the fixed edge of the half element is equal to 2a+e, while the two supporting frames engage each other so that at each end of the electrodes there is a half element.

3. In an electron multiplier tube, a plurality of slatted References Cited by the Examiner UNITED STATES PATENTS 1,410,229 3/1922 Von Vargyas 24046.35 1,632,135 6/1927 Hendry 313348 X 1,674,507 6/ 1928 Ferguson 24046.35 2,070,816 2/1937 Von Wedel 3l3--348 X 2,236,041 3/1941 Teal 313-l05 2,246,172 6/1941 Hergenrother 3l3105 3,039,016 6/1962 Thomson et al 313-105 X FOREIGN PATENTS 807,997 1/1959 Great Britain.

GEORGE N. WESTBY, Primary Examiner;

P. C. DEMEO, Assistant Examiner. 

1. IN AN ELECTRON MULTIPLIER TUBE, A SLATTED ELECTRODE COMPRISING TWO INTERENGAGING FLAT SUPPORTING FRAMES EACH PROVIDED WITH A PLURALITY OF SLAT-LIKE ELEMENTS EXTENDING OUTWARDLY FROM BOTH SIDES OF SAID FRAME AND FORMING AN ANGLE THEREWITH NOT GREATER THAN 90*, EACH OF SAID ELEMENTS BEING CONNECTED TO ONE OF SAID FRAMES BY A TAG OF SMALLER DIMENSIONS THAN THE SLAT-LIKE ELEMENT WHICH IS INTEGRAL THEREWITH AND THE FRAME, ALTERNATE ELEMENTS BEING CONNECTED TO THE RESPECTIVE FRAMES AND BEING SPACED APART A GIVEN DISTANCE SO THAT SAID ELEMENTS INTERLEAVE AND ARE SPACED FROM ONE ANOTHER AN EQUAL DISTANCE. 